Contents

Sound Blaster Live mixer / default DSP code

The EMU10K1 chips have a DSP part which can be
programmed to support various ways of sample processing, which is
described here. (This acticle does not deal with the overall
functionality of the EMU10K1 chips. See the manuals section for further
details.)

The ALSA driver programs this portion of chip by default code (can be
altered later) which offers the following functionality:

IEC958 (S/PDIF) raw PCM

This PCM device (it's the 4th PCM device (index 3!) and first subdevice
(index 0) for a given card) allows to forward 48kHz, stereo, 16-bit
little endian streams without any modifications to the digital output
(coaxial or optical). The universal interface allows the creation of up
to 8 raw PCM devices operating at 48kHz, 16-bit little endian. It would
be easy to add support for multichannel devices to the current code, but
the conversion routines exist only for stereo (2-channel streams) at the
time.

Look to tram_poke routines in lowlevel/emu10k1/emufx.c for more
details.

Digital mixer controls

These controls are built using the DSP instructions. They offer extended
functionality. Only the default build-in code in the ALSA driver is
described here. Note that the controls work as attenuators: the maximum
value is the neutral position leaving the signal unchanged. Note that if
the same destination is mentioned in multiple controls, the signal is
accumulated and can be wrapped (set to maximal or minimal value without
checking of overflow).

This control is used to attenuate samples for left and right PCM FX-bus
accumulators. ALSA uses accumulators 0 and 1 for left and right PCM
samples. The result samples are forwarded to the front DAC PCM slots of
the AC97 codec.

name='Wave Surround Playback Volume',index=0

This control is used to attenuate samples for left and right PCM FX-bus
accumulators. ALSA uses accumulators 0 and 1 for left and right PCM
samples. The result samples are forwarded to the rear I2S DACs. These
DACs operates separately (they are not inside the AC97 codec).

name='Wave Center Playback Volume',index=0

This control is used to attenuate samples for left and right PCM FX-bus
accumulators. ALSA uses accumulators 0 and 1 for left and right PCM
samples. The result is mixed to mono signal (single channel) and
forwarded to the rear right DAC PCM slot of the AC97 codec.

name='Wave LFE Playback Volume',index=0

This control is used to attenuate samples for left and right PCM FX-bus
accumulators. ALSA uses accumulators 0 and 1 for left and right PCM. The
result is mixed to mono signal (single channel) and forwarded to the
rear left DAC PCM slot of the AC97 codec.

name='Wave Capture Volume',index=0name='Wave Capture
Switch',index=0

These controls are used to attenuate samples for left and right PCM
FX-bus accumulator. ALSA uses accumulators 0 and 1 for left and right
PCM. The result is forwarded to the ADC capture FIFO (thus to the
standard capture PCM device).

name='Music Playback Volume',index=0

This control is used to attenuate samples for left and right MIDI FX-bus
accumulators. ALSA uses accumulators 4 and 5 for left and right MIDI
samples. The result samples are forwarded to the front DAC PCM slots of
the AC97 codec.

These controls are used to attenuate samples for left and right MIDI
FX-bus accumulator. ALSA uses accumulators 4 and 5 for left and right
PCM. The result is forwarded to the ADC capture FIFO (thus to the
standard capture PCM device).

name='Surround Digital Playback Volume',index=0

This control is used to attenuate samples for left and right rear PCM
FX-bus accumulators. ALSA uses accumulators 2 and 3 for left and right
rear PCM samples. The result samples are forwarded to the rear I2S DACs.
These DACs operate separately (they are not inside the AC97 codec).

These controls are used to attenuate samples for left and right rear PCM
FX-bus accumulators. ALSA uses accumulators 2 and 3 for left and right
rear PCM samples. The result is forwarded to the ADC capture FIFO (thus
to the standard capture PCM device).

name='Center Playback Volume',index=0

This control is used to attenuate sample for center PCM FX-bus
accumulator. ALSA uses accumulator 6 for center PCM sample. The result
sample is forwarded to the ??rear?? right DAC PCM slot of the AC97
codec.

name='LFE Playback Volume',index=0

This control is used to attenuate sample for center PCM FX-bus
accumulator. ALSA uses accumulator 6 for center PCM sample. The result
sample is forwarded to the ??rear?? left DAC PCM slot of the AC97 codec.

name='AC97 Playback Volume',index=0

This control is used to attenuate samples for left and right front ADC
PCM slots of the AC97 codec. The result samples are forwarded to the
front DAC PCM slots of the AC97 codec.

Note: This control should be zero for the standard operations,
otherwise a digital loopback is activated.

name='AC97 Capture Volume',index=0

This control is used to attenuate samples for left and right front ADC
PCM slots of the AC97 codec. The result is forwarded to the ADC capture
FIFO (thus to the standard capture PCM device).

Note: This control should be 100 (maximal value), otherwise no analog
inputs of the AC97 codec can be captured (recorded).

name='IEC958 TTL Playback Volume',index=0

This control is used to attenuate samples from left and right IEC958 TTL
digital inputs (usually used by a CDROM drive). The result samples are
forwarded to the front DAC PCM slots of the AC97 codec.

name='IEC958 TTL Capture Volume',index=0

This control is used to attenuate samples from left and right IEC958 TTL
digital inputs (usually used by a CDROM drive). The result samples are
forwarded to the ADC capture FIFO (thus to the standard capture PCM
device).

name='Zoom Video Playback Volume',index=0

This control is used to attenuate samples from left and right zoom video
digital inputs (usually used by a CDROM drive). The result samples are
forwarded to the front DAC PCM slots of the AC97 codec.

name='Zoom Video Capture Volume',index=0

This control is used to attenuate samples from left and right zoom video
digital inputs (usually used by a CDROM drive). The result samples are
forwarded to the ADC capture FIFO (thus to the standard capture PCM
device).

name='IEC958 Optical Playback Volume',index=0

This control is used to attenuate samples from left and right IEC958
optical digital input. The result samples are forwarded to the front DAC
PCM slots of the AC97 codec.

name='IEC958 Optical Capture Volume',index=0

This control is used to attenuate samples from left and right IEC958
optical digital inputs. The result samples are forwarded to the ADC
capture FIFO (thus to the standard capture PCM device).

name='IEC958 Coaxial Playback Volume',index=0

This control is used to attenuate samples from left and right IEC958
coaxial digital inputs. The result samples are forwarded to the front
DAC PCM slots of the AC97 codec.

name='IEC958 Coaxial Capture Volume',index=0

This control is used to attenuate samples from left and right IEC958
coaxial digital inputs. The result samples are forwarded to the ADC
capture FIFO (thus to the standard capture PCM device).